MagneSensors, Inc. Phase I SBIR Ultra-sensitive magnetic assays for rapid detection of stroke biomarkers Project Summary Current treatment of stroke is hampered by the need to rapidly determine who can safely benefit from therapeutic intervention. FDA approved thrombolytic therapy can be effective for acute ischemic stroke, the most common stroke, as long as it is administered within the first 3-4.5 hours. Many doctors are reluctant to use thrombolytic therapy since it can be lethal if administered to patients with intracerebral hemorrhage (ICH). A rapid and simple diagnostic test for stroke biomarkers in blood might provide valuable diagnostic information, helping to sort out who should and should not receive therapy. A number of studies have shown glial fibrillary acidic protein (GFAP) to be a promising biomarker. Unfortunately, existing GFAP tests lack adequate sensitivity, are highly variable (not directly quantitative), and take too long. As such, they are inadequate even for clinical studies designed to evaluate the biomarker as well as unsuitable for subsequent clinical application. We hypothesize that a rapid, sensitive, and quantitative blood test for GFAP could provide important diagnostic information for specific clinical applications that include ruling out ICH. Our Phase I goal is to develop such a test to overcome the shortcomings of existing tests. We propose a new approach that is centered on the use of new magnetic nanoparticle labels and ultra-sensitive magnetic sensors, which together offer a unique combination of benefits. To our knowledge, magnetic detection assays have never been applied to the detection of stroke biomarkers. The Phase I specific aim is to demonstrate a magnetic immunoassay for the GFAP stroke biomarker that has: 1) high analytical sensitivity, 2 pg/ml in blood, and 2) rapid turnaround time, 50 minutes total that includes both preparation and measurement. We will also measure GFAP levels in thirty clinical blood specimens collected from ischemic stroke and ICH patients by our UCSD Stroke Center collaborator. The development of the GFAP magnetic test in Phase I will employ a model system where GFAP is spiked into whole blood and captured on microspheres coated with anti-GFAP. Magnetic nanoparticles coated with detect anti-GFAP antibodies then bind to the captured GFAP. The magnetic signal from bound magnetic nanoparticle labels is measured with our latest generation magnetic detection instrument, which is designed for use in a clinical setting. The novel mix and measure format eliminates the need for wash steps to remove unbound magnetic nanoparticle labels or red blood cells, thereby enabling rapid and sensitive tests of blood biomarkers. In Phase II we plan to conduct a much larger prospective clinical study on specimens provided by our UCSD collaborator. We expect to reduce the total test time to 15 minutes or less, which is very important for this time critical application. We also plan to evaluate additional biomarkers to improve clinical sensitivity and specificity. The Phase II goal is to collect convincing data to recruit additional luminary sites t enable multi-center clinical studies in Phase III. Ultimately, we plan to team with a larger company to bring these tests to market. PUBLIC HEALTH RELEVANCE: Nearly 800,000 people have strokes annually in the U.S. leading to 140,000 deaths, making stroke the third leading cause of mortality and the number one cause of long term disability. Proven therapy can significantly reduce damage to brain cells if given in time, but it is currently underutilized as it is difficult to quickly determine when itcan most safely be used. The rapid, sensitive detection of stroke biomarkers in blood could assist early diagnosis to improve patient treatment.